I'm trying to use bone driver/follower to make bones of different actors to interact with each other, but can't really figure it out, since there is no much documentation on it. I've also tried using changing bones position with Get/Set, but for some reason can't find Set bone transform for Spine component.

UE4 currently doesn't have any good 2D collision mechanisms, at least none that they recommend using in production. You will have to approach this like you'd approach it for 3D collisions. A SpineSkeletonRendererComponent does generate a collision mesh which you can use in combination with UE4s 3D physics/collision functions. Alternatively, you could calculate the overlap yourself, but that might be to complicated.